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Running wonderful until....THE FIRE!

Edward Jones
(@14979)
Trusted Member

Let my sorrow be a lesson. A few weeks ago I backed my 1981 R100RT out of the garage to do a carburetor synchronization. I started the bike up normally and fiddled around with something when I heard a hissing noise that I couldn't identify. Next thing I saw was "steam", actually white/gray smoke, poring out of the right combination switch where the wiring enters. My mind froze for a few seconds. Next the wire harness from the combo to the headlight bucket started to "steam" 😯. Now I got my ass in gear. I switched off the ignition SW but the bike continued to run. And the starter started to engage. Some wires in the headlight bucket had melted the insulation and shorted together. I sprinted to my car in the front yard to get my fire extinguisher, sadly it was a dry chemical but certainly better than nothing. The engine has stopped as I sprayed and knocked out the fire but the engine starter kept running and the engine kill switch had melted and popped out. Next task was to disconnect the battery to kill the starter. Ran into the garage to get a screw driver. Flipped open the seat. Luckily I didn't have my 4 gal auxiliary fuel tank on the tail rack as the support bracket needs to be removed to open the seat. Disconnected the negative terminal and finally silence.

Lessons learned from the BMW fire.
1. Always carry a fire extinguisher of CO2 type. Precious seconds were wasted running to the car to get the dry chemical fire extinguisher. Also dry chemical leaves a mess to clean up and is corrosive. I've since gotten small CO2 extinguishers to carry on each bike, BMW, GL1200, KLR650. And have mounted a 10lb bottle in the garage. I had/have another dry chemical in the garage but couldn't remember where it was located, hence the sprint to the car.

2. The Airhead does not have a main fuse. My GL1200 has a 30amp right off the battery and the KLR650 has a 20amp. I estimate that the ignition wiring(starter relay->ignition switch->run/stop switch->coil) had 20amps to 50amp current flow. I'd never really looked at the BMW schematics before. I was shocked to see the only fuses in the system are for turn signals, marker, plate, horn, brake but not the headlight or ignition.  I will be installing a main 30A fuse.

3. A battery cutoff switch should be on each vehicle. I don't know why I haven't thought of this before. I've raced sports cars and motorcycles in the past and they ALWAYS have easy to reach battery cutoff switches. So much less damage would have occurred if I'd been able to simply reach down and cut off battery power.

This will be a belt and suspenders approach with a main fuse and battery cutoff. But I've learned my lesson.

You'll see I posted an wanted ad for the right combo switch. I could put an after market but would like the OE. The picture is the burned unit off my bike.

Edward

 

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Topic starter Posted : 10/03/2021 09:34

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